Primer-casing



J. V. McADAM.

PRIMER CASING.

APPLICATION FILED sEPT.2o. IeIs.

Pagented Dec. M, i929.

lill/l1 UNET SETT PTNT @FFME JOHN V. MCADAM, 0F THE UNITED STATES ARMY, ASSIGNOR TO NEWTON D. BAKER, SECRETARY 0F VTAR, TRUSTEE.

PRIMER-CASING.

Spcciicaton of Letters Patent.

Patented Dec. 14, 1220.

Application led September 20, 1918. Serial No. 255,016.

T 0 all 'whom it may concern:

Be it known that I, JOHN V. MGADAM, major, Ordnance Department, the United States-Army, a citizen of the United States, stationed at lVashington, D. C., in the oiiice of the Chief of Ordnance, have invented an Improvement in Primer-Casings, of which the following is a specification.

rThe invention described herein may be used by the Government, or any of its oiiicers or employees in prosecution of work for the Government, or by any other person in the United States, without the payment of any royalty thereon.

My invention relates to the improvement of rifle grenades in which the bullet preferably of ordinary type passes through an aperture in the grenade after leaving the muzzle of the riiie.

One object of my invention is to improve rifle grenades of this general type and to make their operation more positive and certain than has heretofore been possible.

Another object is to provide means for ignting the fuse of such grenades which shall be positive and certain but which will not be liable to premature operation.

To this end I have provided an improved primer and a striking member therefor which may be used with standard grenades of the type referred to, attaining these objects by the means shown in the accompanying sheet of drawings in which- Figure lis a longitudinal sectional view of a discharger and grenade of the type shown in British Patent 100,700, June, 1916, to Jean Viven and Gustave Bessiere;

Fig. 2 shows the hammer or striking piece on a larger scale;

Fig. 3 shows a longitudinal sectional view of one form of primer embodying my invention;

Fig. 4 shows a slightly modified form of primer.

Referring to Fig. 1, the numeral 1 indicates a fragmentary part of the barrel of a standard military rifle. 2 represents, as a whole, the discharger piece which is attached to the rifle barrel by means of a sleeve 3 fastened to the barrel in any suitable manner. The upper part of the discharger consists of a somewhat larger sleeve 4, which receives the grenade and controls its direction of Hight. rIhe parts 3 and 4 are connected by a conical wall 2.

The grenade itself may consist of a side wall, 6, connecting two end walls, 7 and 8. These end walls are provided with central apertures which receive and support a central tube, 9, having an aperture 10 as large as or slightly larger than the bore of the barrel.

Thehammer or striking piece may be a metallic strip, comprising an apertured supporting base 16, which is gripped between the end wall 7 and the primer casing 19, which casing is threaded into the end wall 7 as -indicated at 14, and an upwardly extending striking wing, 17, which overlies the primer 15. The wing 17 is positioned in the path of the bullet, is struck thereby, and caused to violently strike the primer. The mixture in the primer will be detonated, the powder 18 consumed and the fuse, 12, ignited, which subsequently ignites the blasting cap 12 which explodes the main explosive charge in the space 11, between the wall 6 and the tube 9. The fuse is so timed as to cause explosion of the grenade at about the time its objective is reached.

The wing 17 may be provided with a hump or offset 17 preferably of V shaped cross section which will serve as a ring pin to explode the primer, and with a projection or bent terminal 18 adapted to bear against the primer holding member 19 and thus to hold the wing 17 normally away from the primer except when said wing is struck by a bullet emerging from the bore 10 of central tulle 9, and crushing or tearing off the free en The structure just described provides a combined hammer and safety member which, while held against accidental firing of the primer, operates eiiiciently under the impact of the bullet expelled from the rifle to explode the primer and ignite the fuse of the grenade.

Conveniently, the primer holding member is provided with a threaded basal stem 14, whereby it may be screwed into a complemental threaded aperture in the grenade 7, as shown. i

It was found that grenades of this type frequently failed to explode for the reason that the primer had not been properlyvstruck to detonate its mixture. In such cases it was generally found that the bullet had so completely deformed the wing 17 as to make it incapable of properly striking the primer,

It will be understood that with primers as heretofore known it is necessary to strike the vital spot of the primer to explode it. Center-fire primers must be struck at or very near the center while rim fire primers must be struck near the rim. l

Therefore, if a pointed hump on the wing were origin-ally properly positioned to strike the primer correctly at certain spot any substantial deformation of the wing 17 by the bullet would cause said hump to miss the vital spot of the primer and cause a misfire. These defects 'are overcome by the improved construction illustrated in the present application.

In Fig. 3, the numeral 20 indicates the base and 21 the cylindrical side wall ofV the primer. Connecting these parts is an annular outwardly projected portion 22, which forms the rim of the primer and provides the internal annular recess 22. 23 represents an anvil which may be of any desired construction, but is shown herein as a cup provided at its bottom with an aperture 28. This anvil may be held in place by crimping as at 21. 24 is the priming` mixture which is shown as extending across the entire inside of the base of the primer.

It will be readily understood that if such a primer is struck near the edge, the rim will be buckled up and the primer mixture detonated` or, if struck at the center, the mixure will be detonated between the anvil and the base of the primer. 1t is also evident that the same result will be obtained if the blow is struck at any intermediate point, either by detonation at the rim or at the center or in some cases at both places.

It is to be understood that my invention is not to be limited to the style of anvil shown, as any other satisfactory structure might be used, as, for example, the anvil shown at 23 in Fig. 4.

It is evident that in a primer of this type,

it is necessary to place the mixture at thoseV points only where it can be detonated-e'. e., at the center and rim. I have illustrated a construction in Fig. 4 where the mixture 24 is placed near the center of the base, and the mixture 24 only near the rim. In this way, a considerable amount of the mixture may be saved.

It is seen, therefore, that I have provided a primer which may be exploded by a blow on any part of its base, and which, although of use Wherever a primer may be necessary, is nevertheless of special utility in connection' with rifle grenades of the type described.

When my improved primer is used in a grenade of the type shown in Fig. 1, and the hump, 17, positioned above the rim at its .lowest point, as illustrated, it is clear that if the striking piece is moved over, it will detonate the primer at the rim. If the bullet deforms the striker, the hump may strike the primer at the center or at the rim near the top edge, or at some intermediate points, or all parts at once. ln any case, the vprimer will be discharged and light the fuse. This Ais a result which is obviously unattainable by primers of the types heretofore known. It has been found in practice that by the use of my improved primer, the difficulty of mislires has been A entirely removed.

It is obvious that my invention is not limited to the forms shown, but that modifications may be made without exceeding the scope of the invention set forth in the subjoined claims:

1. The combination with a primer holder, of a hammer comprising a metallic strip having abent portion constituting a safety member adapted to bear against said primer hol-der.

2. The combination with a primer holder, of a hammer comprising a metallic strip having a basal-portion, a wing constituting the hammer proper, and a bent wing terminal adapted to bear against said primer holder and constituting hammer safety means.

The combination with a primer holder having a threaded stem adapted to be screwed into a grenade or the like, of a hammer comprising a metallic strip comprising a basal portion having an aperture through which said stem is adapted to Vproject. a wing constituting the hammer proper, and a bent terminal adapted to bear against said primer holder and constituting hammer safety means.

4. The combination with a rifle grenade apertured for the passage therethrough of a bullet, of a primer-holder carried thereby, and a combined hammer and safety member disposed in proximity to said primer-holder and in the path of movement of .a bullet traversing said grenade aperture.

The combination with a rifle grenade apertured for the passage therethrough of a bullet, of a primer-holder carried, thereby; and a metallic strip comprising a basal portion disposed between the primer-holder and the grenade, a wing, constituting the hammer proper. disposed in the path of movement of a bullet traversing said grenade aperture, and a bent wing-terminal, .constituting hammer safetyV means, Vbearing against said primer-holder.

In testimony whereof I aix my signature.

JOHN v. MOADAMQ 

